Java tutorial
/** * The MIT License * Copyright (c) 2015 Estonian Information System Authority (RIA), Population Register Centre (VRK) * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this software and associated documentation files (the "Software"), to deal * in the Software without restriction, including without limitation the rights * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell * copies of the Software, and to permit persons to whom the Software is * furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice shall be included in * all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN * THE SOFTWARE. */ package ee.ria.xroad.common.messagelog.archive; import static org.apache.commons.lang3.StringUtils.isBlank; import java.nio.charset.StandardCharsets; import java.util.ArrayList; import java.util.List; import ee.ria.xroad.common.util.CryptoUtils; import lombok.Getter; import lombok.SneakyThrows; /** * Creates linking info for the log archive file. */ class LinkingInfoBuilder { private final String hashAlgoId; private final LogArchiveBase archiveBase; private DigestEntry lastArchive; private String lastDigest; @Getter private String createdArchiveLastDigest; @Getter private List<DigestEntry> digestsForFiles = new ArrayList<>(); LinkingInfoBuilder(String hashAlgoId, LogArchiveBase archiveBase) { this.hashAlgoId = hashAlgoId; this.archiveBase = archiveBase; updateLastArchive(); this.lastDigest = lastArchive.getDigest(); } void addNextFile(String fileName, byte[] fileBytes) { String combinedDigests = lastDigest + hexDigest(fileBytes); String currentDigest = hexDigest(combinedDigests.getBytes(StandardCharsets.UTF_8)); digestsForFiles.add(new DigestEntry(currentDigest, fileName)); lastDigest = currentDigest; } void afterArchiveCreated() { digestsForFiles = new ArrayList<>(); createdArchiveLastDigest = lastDigest; lastDigest = lastArchive.getDigest(); } void afterArchiveSaved() { updateLastArchive(); } byte[] build() { StringBuilder builder = new StringBuilder(); builder.append(getWritable(lastArchive.getDigest())).append(" ") .append(getWritable(lastArchive.getFileName())).append(" ").append(hashAlgoId).append('\n'); digestsForFiles.forEach(each -> builder.append(each.toLinkingInfoEntry()).append('\n')); return builder.toString().getBytes(StandardCharsets.UTF_8); } @SneakyThrows private String hexDigest(byte[] fileBytes) { return CryptoUtils.hexDigest(hashAlgoId, fileBytes); } private static String getWritable(String input) { return isBlank(input) ? "-" : input; } @SneakyThrows private void updateLastArchive() { this.lastArchive = archiveBase.loadLastArchive(); } }